In each case, the transition from one term to another was driven by a belief that changing it would somehow reduce racism and increase the social status of black Americans. Unfortunately, I see no evidence that the various changes actually had any such beneficial effect. Indeed, each of these transitions might actually have increased white resentment towards blacks at the margin. As they happened, people who stuck to the old term out of habit would sometimes be accused of racism or racial insensitivity, and such accusations often generate a predictable backlash. Of course, it’s possible that there is data showing that the shift from “Negro” to “black” or that from “black” to “African-American” really did reduce racial prejudice after all. If so, I would be very interested to see it.

Finally, I should emphasize that there is a big difference between these efforts to replace one polite term with another (while stigmatizing the older term), and what I regard as the entirely laudable attempt to stigmatize the use of words such as “kike” or “nigger.” The latter have always been used primarily as racial or ethnic slurs, and understood as such by both speakers and listeners. Not so in the case of words like Negro and black, at least prior to the effort to replace them with new terminology.

UPDATE: Ironically, in Russian the polite term for a black person is “Negr,” while the word for black (“cherny”) is an insult when applied to a person. Racism is very common in Russia, and “cherny” is a generic term of abuse applied to all dark-skinned people, not just those of black African ancestry. Despite this, many Russians living in the US have switched to using “cherny” to refer to blacks when speaking Russian, because “Negr” sounds very similar to the taboo N-word and could cause problems if overheard by non-Russian speakers. Most English-speakers are unaware of the negative connotations of “cherny.”